It can be directly seen that problem (REF ) is non-convex due to the fractional expression of \(\eta _k^{(\text{d},{\text{lb}})}\)  and the \(\log (\cdot )\)  operation in (REF ). In order to solve (REF ), we transform it into the equivalent form in (REF ) which admits suboptimal solutions using the well-known WMMSE approach in [1]}. The details are provided in Appendix E. We summarize the data power control algorithm for D2D links (labeled as `DPCD') in Algorithm REF .
[h]
[1]
Data Power Control Algorithm for D2D Links (DPCD)

Initialize \(f_k=\sqrt{P_k}, w_k=1, \forall k \in {\cal K}\) , and accuracy \(\rho _1\) .
